1. Field of the Invention
This invention relates to a method for filling a liquid into a liquid container having a liquid accommodating chamber, a filling unit for executing the filling method, and a liquid container manufactured according to the filling method. More particularly, the invention relates to a method for filling a liquid into a liquid container used in a liquid discharging apparatus, such as an ink-jet recording apparatus or the like, a filling unit, and a liquid container manufactured according to the filling method.
2. Description of the Related Art
For a liquid container used in a liquid discharging apparatus, particularly an ink cartridge used in an ink-jet recording apparatus, it is required, for example, to reliably supply ink corresponding to the amount of ink discharged from a recording means while the recording means operates, and not to leak ink from discharging ports while the recording means does not operate.
In order to satisfy such conditions, a mechanism for generating a back pressure for ink supplied to the recording means is often used in an ink cartridge. Since the back pressure causes the pressure of discharging ports of the recording means to be negative with respect to the atmospheric pressure, it is called a negative pressure.
One of the easiest ways to generate a negative pressure is to utilize a capillary force of a porous member (negative pressure generating member), such as a sponge or the like. The assignee of the present application has proposed, in Japanese Patent Laid-Open Application (Kokai) No. 7-108688 (1995), a small-size ink-jet cartridge having a high efficiency of use which utilizes such a porous member, and which nevertheless can increase the amount of accommodated ink per unit volume of the ink cartridge and realize stable ink supply.
FIG. 8 is a schematic cross-sectional view illustrating an ink cartridge having the above-described configuration. The inside of an ink cartridge 101 is divided into two spaces by a partition 103 having a communicating hole (communicating portion) 102. One of the spaces is an ink accommodating chamber (second chamber) 104 which is closed except for the communicating hole 102 of the partition 103 and directly holds ink 90 without the ink 80 being mixed with other materials. The other space is a negative-pressure-generating-member accommodating chamber (first chamber) 106 which accommodates a negative pressure generating member 105. An atmospheric-air communicating portion 107 for introducing the atmospheric air into the ink cartridge in accordance with consumption of ink, and a supply port (liquid supply portion) 108 for supplying a recording head with ink are formed in a wall of the negative-pressure-generating-member accommodating chamber 106.
In such a tank structure, when ink 80 in the negative pressure generating member 105 is consumed by the recording head, ink is filled from the ink accommodating chamber 104 into the negative pressure generating member 105 of the negative-pressure-generating-member accommodating chamber 106 through the communicating hole 102 of the partition 103. At that time, while the pressure within the ink accommodating chamber 104 is reduced, air entering from the atmospheric-air communicating portion 107 and passing through the negative-pressure-generating-member accommodating chamber 106 enters the ink accommodating chamber 104 via the communicating hole 102 of the partition 103 to mitigate the reduced pressure within the ink accommodating chamber 104. Accordingly, even if; ink is consumed by the recording head, ink fills the absorbing member (the negative pressure generating member 105) in accordance with the consumed amount of ink, so that the negative pressure generating member 105 holds a constant amount of ink and maintains the negative pressure with respect to the recording head substantially constant, to stabilize ink supply to the recording head.
Particularly, as described in Japanese Patent Laid-Open Application (Kokai) No. 6-40043 (1994), by forming a structure for urging introduction of the atmospheric air (for example, a channel 110 or the like) in the vicinity of the communicating portion between the negative-pressure-generating-member accommodating chamber and the ink accommodating chamber, ink can be supplied in a more advantageous manner. Alternatively, as described in Japanese Patent Laid-Open Application (Kokai) No. 7-108688 (1995), an atmospheric-air communicating portion may be provided at an upper portion of the ink cartridge, and a space (buffer portion) 109 where the negative pressure generating member is absent may be provided in the vicinity of the atmospheric-air communicating portion.
Various methods for injecting ink into an ink cartridge having the above-described configuration are known. In one method, as disclosed in Japanese Patent Laid-Open Application (Kokai) No. 8-090785 (1996), ink is injected by providing an appropriate timing between the posture of the ink tank and opening/closing of the ink supply port and the atmospheric-air communicating portion while always inclining the ink cartridge. In another method, as disclosed in Japanese Patent Laid-Open Application (Kokai) No. 8-132636 (1996), ink is injected while reducing the pressure of the ink cartridge.
As for methods for refilling ink into the above-described ink cartridge, for example, as disclosed in Japanese Patent Laid-Open Application No. 6-226990 (1994), a method is known in which a plug is provided at an upper portion of the ink accommodating chamber, the plug is opened before ink in the negative-pressure-generating-member accommodating chamber is consumed to less than a predetermined amount, and ink is injected from an opening closed by the plug into the ink chamber using a syringe or the like.
The above-described ink injection methods are satisfactory from the viewpoint of assuredly injecting ink into an ink cartridge without causing leakage of ink.
For future use, however, in accordance with the recent rapid spread of ink-jet recording apparatuses, it is desired to provide the market with lower-cost ink cartridges, and to provide a low-cost and high-productivity ink injection method in an ink injection process in a process for manufacturing ink tanks.
From such a viewpoint, although the above-described small-size ink cartridge has a high efficiency of use and satisfies the condition of low cost, most of the conventional ink injection methods have a complicated injection process or require a particular apparatus for ink injection.
Furthermore, although the above-described ink refilling method uses a simple injection apparatus, the ink cartridge must in most cases be held in an awkward position during ink injection.
It is an object of the present invention to provide a liquid container, such as the above-described small-size ink cartridge having a high efficiency of use, or the like, with a simple and high-productivity liquid filling method in which a liquid is filled without greatly changing the position or posture of the container, and without using a complicated process or apparatus.
It is another object of the present invention to provide a liquid filling method having a high accuracy in ink injection into the above-described liquid container.
It is still another object of the present invention to provide a liquid filling method capable of performing more stable liquid supply when using the above-described liquid container.
It is yet another object of the present invention to provide a filling unit and the like which utilize the above-described liquid filling methods.
One aspect of the present invention which achieves these objectives relates to a liquid filling method for filling a liquid into a liquid container, the liquid container including a first chamber incorporating a negative pressure generating member and including a liquid supply portion and an atmospheric-air communicating portion, and a second chamber including a communicating portion communicating with the first chamber and forming a substantially closed space. The method includes the step of prohibiting discharge of air within one of the first chamber and the second chamber, and simultaneously filling a liquid into the other chamber within the other chamber to the outside of the liquid container, in a state in which the communicating portion is placed at a lower position in a direction of gravity. Thus, a simple and high-productivity liquid filling method is realized without using complicated process and apparatus.
This liquid filling method can be applied not only to liquid injection in a process for manufacturing a liquid container, but also to a refilling operation performed after or during the use of a liquid container. That is, the liquid filling method of the present invention can be applied not only to an initial filling operation, but also to a refilling operation after the use of a liquid container has been started.
By using the above-described liquid filling method, a less expensive and high-productivity liquid filling operation for the above-described liquid container can be realized. More preferably, an opening for discharging air may be provided in each of the first chamber and the second chamber, or a region where ink is not filled may be provided near an upper surface of the first chamber.
Another aspect of the present invention which achieves these objectives relates to a liquid filling method for filling a liquid into a liquid container, the liquid container including a first, chamber incorporating a negative pressure generating member and including a liquid supply portion and an atmospheric-air communicating portion, and a second chamber including a communicating portion communicating with the first chamber and forming a substantially closed space. The method includes the step of prohibiting discharge of air within one of the first chamber and the second chamber by blocking the communicating portion with the liquid, and simultaneously filling a liquid into the other chamber while discharging air within the other chamber to the outside of the liquid container. Thus, a simple and high-productivity liquid filling method having a high accuracy in injection is realized without using a complicated process or apparatus.
Particularly, by providing a channel for introducing air at a portion near the communicating portion, the first chamber can immediately block the communicating portion with the liquid. Hence, a filling operation with a higher speed can be performed.
Particularly, when applying this filling method to an initial filling operation, by first filling the liquid into the first chamber, and then filling the liquid into the second chamber, a high-productivity liquid filling method can be provided even when accommodating a liquid or the like which is less well adapted to the negative pressure generating member.
Still another aspect of the present invention which achieves these objectives: relates to a liquid filling method for filling a liquid into a liquid container, the liquid container including a first chamber incorporating a negative pressure generating member and including a liquid supply portion to be connected to a liquid discharging head and an atmospheric-air communicating portion, a second chamber including a communicating portion communicating with the first chamber and forming a substantially closed space, an opening provided at an upper surface of the second chamber, and a region where ink is not filled provided near an upper surface of the first chamber. The method includes the step of prohibiting discharge of air within one of the first chamber and the second chamber by blocking the communicating portion by filling a liquid from a portion of the first chamber near the communicating portion, and simultaneously filling the liquid into the other chamber while discharging air within the other chamber to the outside of the liquid container. Thus, a simple and high-productivity liquid filling method which has a high accuracy in injection and which can perform more stable liquid supply when using the above-described liquid container is realized.
Yet another aspect of the present invention which achieves these objectives relates to a liquid filling method for filling a liquid into a liquid container, the liquid container including a first chamber incorporating a negative pressure generating member and including a liquid supply portion to be connected to a liquid discharging head and an atmospheric-air communicating portion, and a second chamber including a communicating portion communicating with the first chamber and forming a substantially closed space, an opening provided at an upper surface of the second chamber, and a region where ink is not filled provided near an upper surface of the first chamber. The method includes the step of prohibiting discharge of air within one of the first chamber and the second chamber, and simultaneously filling a liquid into the other chamber from the liquid supply portion of the first chamber while discharging air within the other chamber to the outside of the liquid container. Thus, a simple liquid filling method which can perform more stable liquid supply when using the above-described liquid accommodating receptacle is realized.
Yet a further aspect of the present invention which achieves these objectives relates to a liquid filling unit for performing a liquid filling method for a liquid container, the liquid container including a first chamber incorporating a negative pressure generating member, and including a liquid supply portion and an atmospheric-air communicating portion, and a second chamber including a communicating unit communicating with the first chamber and forming a substantially closed space. The method includes the steps of prohibiting discharge of air within one of the first chamber and the second chamber and simultaneously filling a liquid into the other chamber while discharging air within the other chamber to the outside of the liquid container, in a state of a posture in which the communicating portion is placed at a lower position in a direction of gravity, and performing sealing in order to cause the second chamber to be a closed space except for the communicating portion. The filling unit includes a liquid filling unit for injecting a liquid stored therein into the liquid container, a refilling station for controlling the discharge of air, and a seal member for causing the second chamber to be a closed space except for the communicating portion. Thus, a filling unit which utilizes a simple and high-productivity liquid filling method is realized.
Still a further aspect of the present invention which achieves these objectives relates to a liquid container including a first chamber including a liquid supply portion to be connected to a liquid discharging head, and an atmospheric-air communicating portion, and incorporating a negative pressure generating member, and a second chamber, including a communicating portion communicating with the first chamber and forming a substantially closed space. The liquid container is manufactured by prohibiting discharge of air within one of the first chamber and the second chamber and simultaneously filling a liquid into the other chamber while discharging air within the other chamber to the outside of the liquid container, in a state in which the communicating portion is present at a lower position in a direction of gravity, and causing the second chamber to be a closed space except for the communicating portion.
In the foregoing description, the upper surface of the liquid container indicates a surface facing the bottom surface. When the upper surface is present at an upper position, the communicating portion is placed at a lower position in a direction of gravity.
The region where ink is not filled provided near an upper surface of the liquid container indicates not only a space where the negative pressure generating member is absent (a buffer portion), but also a portion where ink is not filled even if the negative pressure generating member is present.
In the following descriptions of the chambers in the liquid container, the expressions xe2x80x9cnegative-pressure-generating-member accommodating chamberxe2x80x9d and xe2x80x9cink (liquid) accommodating chamberxe2x80x9d are used when the chamber concerned is in a condition of holding/accommodating ink (liquid), while the expressions xe2x80x9cfirst chamberxe2x80x9d and xe2x80x9csecond chamberxe2x80x9d are used in a broader sense when the chamber concerned is suitable for holding/accommodating ink (liquid), for example, when the chamber concerned has an opening dedicated for filling ink.
The foregoing and other objects, advantages and features of the present invention will become more apparent from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings.